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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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/*
 *
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 * Copyright (c) 2004 World Wide Web Consortium,
 *
 * (Massachusetts Institute of Technology, European Research Consortium for
 * Informatics and Mathematics, Keio University). All Rights Reserved. This
 * work is distributed under the W3C(r) Software License [1] in the hope that
 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
 */

package org.w3c.dom.ls;

import org.w3c.dom.Node;
import org.w3c.dom.Element;

/**
 * <code>LSParserFilter</code>s provide applications the ability to examine nodes as they are being
 * constructed while parsing. As each node is examined, it may be modified or removed, or the entire
 * parse may be terminated early. <p> At the time any of the filter methods are called by the
 * parser, the owner Document and DOMImplementation objects exist and are accessible. The document
 * element is never passed to the <code>LSParserFilter</code> methods, i.e. it is not possible to
 * filter out the document element. <code>Document</code>, <code>DocumentType</code>,
 * <code>Notation</code>, <code>Entity</code>, and <code>Attr</code> nodes are never passed to the
 * <code>acceptNode</code> method on the filter. The child nodes of an <code>EntityReference</code>
 * node are passed to the filter if the parameter "<a href='http://www.w3.org/TR/DOM-Level-3-Core/core.html#parameter-entities'>
 * entities</a>" is set to <code>false</code>. Note that, as described by the parameter "<a
 * href='http://www.w3.org/TR/DOM-Level-3-Core/core.html#parameter-entities'> entities</a>",
 * unexpanded entity reference nodes are never discarded and are always passed to the filter. <p>
 * All validity checking while parsing a document occurs on the source document as it appears on the
 * input stream, not on the DOM document as it is built in memory. With filters, the document in
 * memory may be a subset of the document on the stream, and its validity may have been affected by
 * the filtering. <p> All default attributes must be present on elements when the elements are
 * passed to the filter methods. All other default content must be passed to the filter methods. <p>
 * DOM applications must not raise exceptions in a filter. The effect of throwing exceptions from a
 * filter is DOM implementation dependent. <p>See also the <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407'>Document
 * Object Model (DOM) Level 3 Load and Save Specification</a>.
 */
public interface LSParserFilter {
  // Constants returned by startElement and acceptNode
  /**
   * Accept the node.
   */
  public static final short FILTER_ACCEPT = 1;
  /**
   * Reject the node and its children.
   */
  public static final short FILTER_REJECT = 2;
  /**
   * Skip this single node. The children of this node will still be
   * considered.
   */
  public static final short FILTER_SKIP = 3;
  /**
   * Interrupt the normal processing of the document.
   */
  public static final short FILTER_INTERRUPT = 4;

  /**
   * The parser will call this method after each <code>Element</code> start
   * tag has been scanned, but before the remainder of the
   * <code>Element</code> is processed. The intent is to allow the
   * element, including any children, to be efficiently skipped. Note that
   * only element nodes are passed to the <code>startElement</code>
   * function.
   * <br>The element node passed to <code>startElement</code> for filtering
   * will include all of the Element's attributes, but none of the
   * children nodes. The Element may not yet be in place in the document
   * being constructed (it may not have a parent node.)
   * <br>A <code>startElement</code> filter function may access or change
   * the attributes for the Element. Changing Namespace declarations will
   * have no effect on namespace resolution by the parser.
   * <br>For efficiency, the Element node passed to the filter may not be
   * the same one as is actually placed in the tree if the node is
   * accepted. And the actual node (node object identity) may be reused
   * during the process of reading in and filtering a document.
   *
   * @param elementArg The newly encountered element. At the time this method is called, the element
   * is incomplete - it will have its attributes, but no children.
   * @return <ul> <li> <code>FILTER_ACCEPT</code> if the <code>Element</code> should be included in
   * the DOM document being built. </li> <li> <code>FILTER_REJECT</code> if the <code>Element</code>
   * and all of its children should be rejected. </li> <li> <code>FILTER_SKIP</code> if the
   * <code>Element</code> should be skipped. All of its children are inserted in place of the
   * skipped <code>Element</code> node. </li> <li> <code>FILTER_INTERRUPT</code> if the filter wants
   * to stop the processing of the document. Interrupting the processing of the document does no
   * longer guarantee that the resulting DOM tree is XML well-formed. The <code>Element</code> is
   * rejected. </li> </ul> Returning any other values will result in unspecified behavior.
   */
  public short startElement(Element elementArg);

  /**
   * This method will be called by the parser at the completion of the
   * parsing of each node. The node and all of its descendants will exist
   * and be complete. The parent node will also exist, although it may be
   * incomplete, i.e. it may have additional children that have not yet
   * been parsed. Attribute nodes are never passed to this function.
   * <br>From within this method, the new node may be freely modified -
   * children may be added or removed, text nodes modified, etc. The state
   * of the rest of the document outside this node is not defined, and the
   * affect of any attempt to navigate to, or to modify any other part of
   * the document is undefined.
   * <br>For validating parsers, the checks are made on the original
   * document, before any modification by the filter. No validity checks
   * are made on any document modifications made by the filter.
   * <br>If this new node is rejected, the parser might reuse the new node
   * and any of its descendants.
   *
   * @param nodeArg The newly constructed element. At the time this method is called, the element is
   * complete - it has all of its children (and their children, recursively) and attributes, and is
   * attached as a child to its parent.
   * @return <ul> <li> <code>FILTER_ACCEPT</code> if this <code>Node</code> should be included in
   * the DOM document being built. </li> <li> <code>FILTER_REJECT</code> if the <code>Node</code>
   * and all of its children should be rejected. </li> <li> <code>FILTER_SKIP</code> if the
   * <code>Node</code> should be skipped and the <code>Node</code> should be replaced by all the
   * children of the <code>Node</code>. </li> <li> <code>FILTER_INTERRUPT</code> if the filter wants
   * to stop the processing of the document. Interrupting the processing of the document does no
   * longer guarantee that the resulting DOM tree is XML well-formed. The <code>Node</code> is
   * accepted and will be the last completely parsed node. </li> </ul>
   */
  public short acceptNode(Node nodeArg);

  /**
   * Tells the <code>LSParser</code> what types of nodes to show to the method
   * <code>LSParserFilter.acceptNode</code>. If a node is not shown to the filter using this
   * attribute, it is automatically included in the DOM document being built. See
   * <code>NodeFilter</code> for definition of the constants. The constants
   * <code>SHOW_ATTRIBUTE</code> , <code>SHOW_DOCUMENT</code>, <code>SHOW_DOCUMENT_TYPE</code>,
   * <code>SHOW_NOTATION</code>, <code>SHOW_ENTITY</code>, and <code>SHOW_DOCUMENT_FRAGMENT</code>
   * are meaningless here. Those nodes will never be passed to <code>LSParserFilter.acceptNode</code>.
   * <br> The constants used here are defined in [<a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113'>DOM
   * Level 2 Traversal and      Range</a>] .
   */
  public int getWhatToShow();

}
